The present invention relates to a magnetic valve for liquid and gaseous media.
In attempting to reduce the dimensions of known magnetic valves of this type, one rapidly encounters a limit at which particularly the necessary fine manufacturing tolerances can no longer be maintained. Efforts toward miniaturization were therefore directed towards valves having a control piston. But even in these instances, the minimum dimensions are still relatively large in view of the difficult machining and necessary manufacturing tolerances.
The geometric shape of the core, which is formed as a flat-body slide, permits maintenance of very fine tolerances, even with minimal dimensions. This permits not only a much greater degree of miniaturization of the valve according to the invention; but additionally core can also be manufactured with an extremely low mass, which allows extremely short valve reaction times to be attained.
The magnetic valve according to the invention can be formed as a constant, quasi-constant, monostable, bistable or tristable valve. The valve therefore can be driven with more than just two or three switch positions. Rather, the flat-body slide can also assume any intermediate positions between its end positions as is necessary, for example, for constant and quasi-constant method of operation. Finally, the magnetic valve according to the invention can be formed not only as a three-way valve, but also as a four and five-way valve. Due to the short switch times, the small stroke and the low inertial mass, which are realized with the magnetic valve according to the invention, it is also possible to control the valve by means of a modulation in the frequency and/or the amplitude and/or the mark-to-space ratio of the electrical control signals, so that even a quasi-constant regulation is possible. In a constant and quasi-constant operation, tolerances in the range of a few thousands of a millimeter are necessary with regard to the position of the control edges relative to each other. The resulting expensive grinding of annular grooves required in known valves with elongated piston slides and the expensive inside lapping of bushings can be replaced in the solution according to the invention by the substantially less expensive circular grinding and outside lapping of plates.
It is preferred that the flat-body slide have the shape of a cylindrical pipe, circular both inside and outside. This reduces the mass, as compared to a disc, which is advantageous for small, rapid switch valves. In addition, the inner chamber of the flat-body slide can be used as a connecting channel between the two valve plates, thus substantially simplifying the channel system, which leads to lower costs and to smaller dimensions of the valve. A flat-body slide in the form of a pipe or ring also makes it possible to realize at relatively low expense both an inner and an outer control edge with very high precision with regard to position and spacing. This eliminates dead travel and achieves a strict linearity between movement and degree of opening, which is particularly important for constant valves such as servo-valves.
Advantageously, the flat-body slide consists of at least two coaxial nesting sleeves. The flat-body slide can in this manner better be adapted to different requirements than with a one-piece embodiment.